Preparation of ethers

ABSTRACT

Symmetrical ethers are prepared by reacting an organic compound containing a halogen or alkyl sulfate group with an alkali metal hydroxide, in aqueous solution, in the presence of a catalytic amount of an organic quaternary salt and recovering from the reaction mixture the desired symmetrical ether. Typical examples of materials used are: 3-chloropropene, sodium hydroxide and trioctyl methyl ammonium chloride. The ethers are useful as solvents.

United States Patent [191 Gordon Oct. 21, 1975 [73] Assignee:Continental Oil Company, Ponca City, Okla 22 Filedz Mar. 25, 1974 21Appl. No.: 454,040

Related US. Application Data [62] Division of Ser. No. 233,771, March10, 1972, Pat.

[52] US. Cl 260/611 A [51] Int. Cl. C07C 41/00 [58] Field of Search260/614, 615 R, 611 A [56] References Cited UNITED STATES PATENTS1,245,742 11/1917 Lacy 260/614 R 1,379,362 5/1921 Riesenfeld... 260/614R X 1,752,049 3/1930 Young 260/654 D 2,181,297 11/1939 Britton et a1260/614 R X 2,237,241 4/1941 Strosacker et al. 260/614 R X 2,285,3296/1942 Coleman et a1 260/654 D X 2,291,375 7/1942 Cass 260/654 D2,755,319 7/1956 Baggett 260/654 D X 2,879,311 3/1959 Hawkins 260/654 D2,989,570 6/1961 Conrad et al. 260/654 D FORElGN PATENTS OR APPLICATIONS343,930 ll/l92l Germany 260/611 A OTHER PUBLICATIONS Olivier, Rec. Trav.Chim. des Pays Bas. 55 (1936), 1034-1035.

Primary Examiner-Howard T. Mars Attorney, Agent, or FirmBayless E.Rutherford, Jr.

[57] ABSTRACT Symmetrical ethers are prepared by reacting an organiccompound containing a halogen or alkyl sulfate group with an alkalimetal hydroxide, in aqueous solution, in the presence of a catalyticamount of an organic quaternary salt and recovering from the reactionmixture the desired symmetrical ether. Typical examples of materialsused are: 3-chloropropene, sodium hydroxide and trioctyl methyl ammoniumchloride. The ethers are useful as solvents.

14 Claims, N0 Drawings 1 PREPARATION OF ETHERS This is a division ofapplication Ser. No 233,771, filed Mar. 10, 1972, now U.S. Pat. No.3,824,295.

TO THE RELATED APPLICATIONS Ser. No. 233,714, entitled Preparation ofAlcohols and Ethers", wherein the inventor is Charles M. Starks, filedthe same day as the p'resentapplication and having the same assignee asthe present application, concerns the preparation of alcohols and ethersby the reaction of an organic compound, containing a halogen or alkylsulfate with an alkali metal hydroxide, in the presence of a catalyticamount of a betaine. In general the betaines give better results athigher temperatures than do the quaternary salts disclosed and claimedherein.

BACKGROUND PRIOR ART From a search of the prior art, the followingreferences are considered to be the most pertinent and/or typical of theprior art.

U.S. Pat. No. 1,379.,3 62 broadly teaches the preparation of dimethylether by the reaction of methyl chloride and an alcoholic solution ofsodium hydroxide. The patent further teaches that in order to make theprocess commercially useful, high pressures (e.g., 20 atmospheres) arerequired.

U.S. Pat. No. 1,873,538 teaches the preparation of dipropyl ether byreacting propyl chloride and sodium hydroxide to form propyl alcohol anddehydrating the propyl alcohol using sulfuric acid to form the dipropylether.

U.S. Pat. No. 2,237,241 teaches the preparation of symmetrical ethers byreacting analkyl halide with a metal hydroxide, using as the catalystvarious polyhydric alcoholsor hydroxy'ethers; I

Briefly, noneof the references discussed in the foregoing teach myprocess, as described herein.

BRIEF SUMMARY ;OF THE INVENTION Broadly stated, my invention is directedto a process for preparing symmetrical ethers by reacting an organiccompound containinga halogen or alkyl sulfate group with an alkali metalhydroxide, in aqueous solution, in the presence of a catalytic amount ofan organic quaternary salt and recovering from the reaction mixture thedesired symmetrical ether. 1

Preferably, the organic compound is a halogensubstituted hydrocarbon. 7

An important feature of the process is the use of the quanternary salt,which will be described in detail herelnafter.

Other significant features of the process are that it is conducted underautogeneous pressure conditions and does not require the use of anorganic solvent.

DETAILED DESCRIPTION Materials used and Amounts of Materials UsedSuitable organic compounds include the following:

a. Primary n-alkyl halides or alkyl sulfates, represented by the formulaRZ wherein R is a C to C normal alkyl group and Z is a halogen or analkyl sulfate group. Preferably, Z is chloride or bromide. Specificexamplesinclude methyl chloride, methyl bromide, butyl chloride, butylbromide, butyl iodide, hexyl chloride, hexyl bromide, octadecylchloride, octadecyl bromide, methylethylsulfate, butylmethylsulfate,hexylmethylsulfate, octadecylmethylsulfate, and octadecylethylsulfatelb. Dihaloalkanes represented by the formula X(CI-I ),,X wherein X'is ahalogen, preferably chlorine or bromine, and n is an integer of 1 to 20.Specific examples include dichloroethane, dibromopropane,dichlorobutane, dichlorooctane, di-

bromododecane, dichlorohexadecane, dib romooctadecane, anddichlbroeicosane/ I Internally substituted mono-, di-, andpolychlorinated or brominated alkanes containing 4 to 40 carbon atoms.Preferably, the chlorinated alkanes are monoor di-substituted. Specificexam:

ples include 2-chlorobutane, 2,4-dichloropentane,

2-chlorohexane, 2,6-dichlorooctane, 2,1 8-

dichloroeicosane, 2,6,18-trichloroeicosane, 2,28-

dichlorotriacontane, 2,20,28-trichlorotriacontane,

2,38-dibromotetracontane, 2,38-

dichlorotetracontane, and 2,20,38-trichlorotetracontane.

d. Unsaturated alkyl halides containing 3 to 40 carbon atoms, such asl-chloro-3-propene, 1,4- dichloro-2-butene, 2,6-dichloro-4-octene, 2,8-dichloro-6-decene, 2,1 8-dichlorol O-eicosene, 2,18-dibromo-lO-eicosene,2,28-dichloro-20- triacontene, 2 ,34-dibromo-4-dotriaconte ne, 4-chloro-1 triacontene, and 2 ,3 8-dibromo- 10- tetracontene. 1

e. Monoand di-chloro-substituted monocyclic aromatic compounds, such asbenzyl chloride and a, a-dichloroxylene f. Compounds of the type Y (Cl-1),,Z wherein n is an integer of l to 20, Z is chloride, bromide, iodide,

' or an alkylsulfate group and Y is a nonreactive functional group suchas CN or NH,.

Of the foregoing materials the chlorinated or brominated hydrocarbonsare considered more suitable, with the n-alkyl chlorides or bromidesbeing preferred for reasons of economy and availability. 7

An aqueous solution of alkali metal hydroxide is used. More suitably,the alkali metal is sodium or potassium, but preferably is sodium, foreconomic reasons. The concentrations of the alkali metal in the watercan be in the range of 1 to Preferably, the concentration is not lessthan 10% by weight.

While it is suitable to use stoichiometric amounts of the organiccompound and alkali metal hydroxide (i.e., 1:1 mole ratio), preferablyan excess of alkali metal hydroxide is used which can be .in the rangeof 2 to 5 times the stoichiometric amount.

The amount of alkali metal hydroxide suitably used,

based on the halogenated hydrocarbon, on a molar basis, is in the rangeof about 1:1 to about :1.

The more suitable organic quaternary salts, which are used as a catalystin my invention, have the general formula wherein M is a pentavalent ionof an element selected from the group consisting of nitrogen,phosphorus, arsenic, antimony and bismuth, R R R and R are alkyl groupscontaining from 1 to about 30 carbon atoms, and Z is a conventionalanion derived from an organic or inorganic acid, including halides,sulfates, alkyl sulfates, sulfonates and acetates. Normally, it isdesirable that the alkyl substituents R R R and R contain more than asingle carbon atom. Examples of suitable organic quaternary salts whichcan be employed as the catalyst for the exchange reaction describedhereinbefore are: hexadecyltrihexylammonium bromide;trioctylethylammonium bromide; tridecylmethylammonium chloride;diodecyldimethylammonium chloride; tetraheptylammonium iodide;dioctadecyldimethyl ammonium chloride; tridecylbenzylammonium chloride;tributyldecylphosphonium iodide; triphenyldecylphosphonium iodide;tributylhexadecylphosphonium iodide; tricapryldodecylammonium ptoluenesulfonate; tribenzyldecylarsonium chloride; tetranonylammoniumhydroxide; N,N,N',N'- tetramethyl-N,N'-ditetradecyl p-xylene-a,a'-diammonium dichloride; l-methyl-l-(N-octadecanonyl-Z-aminoethyl)-2-heptadecyl-4,5-dihydro-1,3-diazole methyl sulfonate;N,N,N',N'-tetramethyl-N,N'- dictadecyl-x-dodecyl-y-xylene-a,a-dioctadecyl-xdodecyl-y-xylene-a-diammonium dichloride.

The preferred organic quaternary salts are those wherein M is nitrogenor phosphorus and Z is chloride or bromide ion. The most preferredorganic quaternary salts are those wherein M is nitrogen and Z ischloride or bromide.

Knowing that the quaternary salts described herein are effective as acatalyst in the process of preparing symmetrical ethers describedherein, any person'skilled in the art can readily determine the optimumamount required. In order to make my disclosure more complete, however,1 have found a preferred amount of catalyst to be from about 1 to about5 percent by weight based on the organic compound. An amount of catalystas low as 0.01 weight percent is suitable provided a longer reactiontime is not undesirable. Similarly, an amount of catalyst as high asabout 20 weight percent is suitable as long as higher costs are notundesirable.

Process Conditions The process can be conducted under either batch orcontinuous operation, but usually is conducted as a batch operation.

The process can be conducted at a temperature in the range of 0 to300C., more suitably to 150C., and preferably about 30 to about 50C.

The reaction time is not critical, being dependent on the particularmaterials used (e.g., type of organic compound, type of catalyst andconcentration of catalyst and/or alkali metal hydroxide).

No solvent is required other than the water for making an aqueous alkalimetal hydroxide' solution.

The reaction is conducted under autogeneous pressure, in other wordstheonly pressure is that which is self-generated by the materials andprocess conditions. It is not necessary to use intentionally createdconditions in order to produce a higher pressure in the reaction system.7 1

Upon completion of the reaction the desired symmetrical ether is removedfrom the reaction mass by distillation. l I

in order to disclose the'nature of the present invention morespecifically, the following illustrative examples will be given. his tobe understood that the invention is not to be limited to the specificconditions or details set forth in these examples except insofar asthese limitations are specified in the appended claims.

EXAMPLE 1 EXAMPLE 2 Diallyl ether is prepared using the conditions ofExample except it is removed from the reaction mixture by means ofdistillation.

EXAMPLES Using the conditions of Example 1, dibutyl ether is preparedusing n-butyl chloride, 50% aqueous NaOH solution and tridecyl methylammonium chloride. The product is separated from the reaction mixture bymeans of distillation.

EXAMPLE 4 7 Using the conditions of Example 1, di-2-hexyl ether isprepared using 2-chlorohexane, 50% aqueous NaOH solution andtridecylbenzylammonium chloride. The product is separated from thereaction mixture by means of distillation.

Having thus described the invention by providing specific examplesthereof, it is to be understood that no undue limitations orrestrictions are to be drawn by reason thereof and that many variationsand modifications are within the scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured'by Letters Patent is:

l. A process for preparing symmetrical ethers wherein the processcomprises reacting halogenated hydrocarbons containing from 1 to 40carbon'atoms, with an alkali metal hydroxide, in aqueous solution, ata'temperature in the range of about 30 to about 50C, in the presence ofa catalytic amount, in the range of from about 0.01 to about 20 weightpercent, based on said organic compound, of a quaternary salt andrecovering from the reaction mixture by distillation the deized furtherin that:

A. the quaternary salt is represented by the formula:

wherein (1) M is a pentavalent ion of an element selected from the groupconsisting of nitrogen, phosphorus, arsenic, antimony, and bismuth; (2)R R R and R are alkyl groups containing from 1 to about 30 carbon atoms;and (3) Z is an anion selected from the group consisting of halides,sulfates, alkyl sulfates, sulfonates, and acetates;

B. the halogenated hydrocarbon is selected from the C. the amount ofalkali metal hydroxide, based on said halogenated hydrocarbon, on amolar basis, is in the range of about 1:1 to about 5:1. 2. The processof claim 1 wherein the alkali metal hydroxide is sodium hydroxide, theamount of alkali metal hydroxide is from 2 to 5 moles per mole ofhalogenated hydrocarbon, and the amount of quaternary salt catalyst isfrom about 1 to about 5 weight percent,

based on the halogenated hydrocarbon.

3. The process of claim 2 wherein, in the quaternary salt, M is nitrogenand Z is a halide anion.

4. The process of claim 3 wherein the halide anion is chloride.

5. The process of claim 4 wherein the halogenated hydrocarbon is adihaloalkane represented by the formula X(Cl-l ),,X wherein X is achloride or bromide anion and n is an integer of from 1 to 20.

6. The process of claim 4 wherein the halogenated hydrocarbon is aninternally substituted mono-, diand trichlorinated or brominated alkanecontaining from 4 to 40 carbon atoms.

7. The process of claim 4 wherein the halogenated hydrocarbon is anunsaturated alkyl halide containing 3 to 40 carbon atoms.

8. The process of claim 4 wherein the halogenated hydrocarbon is benzylchloride or a, a-dichloroxylene.

9. The process of claim 3 wherein, in the quaternary salt, M isphosphorous and Z is a halide anion.

10. The process of claim 9 wherein the halide anion is chloride.

11. The process of claim 10 wherein the halogenated hydrocarbon is adihaloalkane represented by the formula X(CH ),,X wherein X is achloride or bromide anion and n is an integer of from 1 to 20.

12. The process of claim 10 wherein the halogenated hydrocarbon is aninternally substituted mono-, di-, and tri-chlorinated or brominatedalkane containing from 4 to 40 carbon atoms.

13. The process of claim 10 wherein the halogenated hydrocarbon is anunsaturated alkyl halide containing 3 to 40 carbon atoms.

14. The process of claim 10 wherein the halogenated hydrocarbon isbenzyl chloride or a, a-dichloroxylene. =l

1. A PROCESS FOR PREPARING SYMMETRICAL ETHERS WHEREIN THE PROCESSCOMPRISES REACTING HALOGENATED HYDROCARBONS CONTAINING FROM 1 TO 40CARBON ATOMS WITH AN ALKALI METAL HYDROXIDE IN AQUEOUS SOLUTION AT AEMPERATURE IN THE RANGE OF ABOUT 30* TO ABOUT 5/*C IN THE PRESENCE OF ACATAYTIC AMOUNT IN THE RANGE OF FROM ABOUT 0.01 TO ABOUT 20 WEIGHTPERCENT BASED ON SAID ORGANIC COMPOUND OF A QUATERNARY SALT ANDRECOVERING FROM THE REACTION MIXTURE BY DISTILLATION THE DESIREDSYMMETRICAL ETHER SAID PROCESS BEING CHARACTERIZED FURTHER IN THAT: A.THE QUATERNARY SALT IS REPRESENTED BY THE FORMULA:
 2. The process ofclaim 1 wherein the alkali metal hydroxide is sodium hydroxide, theamount of alkali metal hydroxide is from 2 to 5 moles per mole ofhalogenated hydrocarbon, and the amount of quaternary salt catalyst isfrom about 1 to about 5 weight percent, based on the halogenatedhydrocarbon.
 3. The process of claim 2 wHerein, in the quaternary salt,M is nitrogen and Z is a halide anion.
 4. The process of claim 3 whereinthe halide anion is chloride.
 5. The process of claim 4 wherein thehalogenated hydrocarbon is a dihaloalkane represented by the formulaX(CH2)nX wherein X is a chloride or bromide anion and n is an integer offrom 1 to
 20. 6. The process of claim 4 wherein the halogenatedhydrocarbon is an internally substituted mono-, di- and tri-chlorinatedor brominated alkane containing from 4 to 40 carbon atoms.
 7. Theprocess of claim 4 wherein the halogenated hydrocarbon is an unsaturatedalkyl halide containing 3 to 40 carbon atoms.
 8. The process of claim 4wherein the halogenated hydrocarbon is benzyl chloride or Alpha , Alpha''-dichloroxylene.
 9. The process of claim 3 wherein, in the quaternarysalt, M is phosphorous and Z is a halide anion.
 10. The process of claim9 wherein the halide anion is chloride.
 11. The process of claim 10wherein the halogenated hydrocarbon is a dihaloalkane represented by theformula X(CH2)nX wherein X is a chloride or bromide anion and n is aninteger of from 1 to
 20. 12. The process of claim 10 wherein thehalogenated hydrocarbon is an internally substituted mono-, di-, andtri-chlorinated or brominated alkane containing from 4 to 40 carbonatoms.
 13. The process of claim 10 wherein the halogenated hydrocarbonis an unsaturated alkyl halide containing 3 to 40 carbon atoms.
 14. Theprocess of claim 10 wherein the halogenated hydrocarbon is benzylchloride or Alpha , Alpha ''-dichloroxylene.